Exclusive catalytic hydrogenation of nitrobenzene toward -aminophenol over atomically precise Au(SR) clusters.

Despite the advances in devising green methodologies for selective hydrogenation of nitrobenzene toward -aminophenol, it is still difficult to realize -aminophenol as the exclusive product in heterogeneous metal catalysis, as the excessive hydrogenation of nitrobenzene usually results in the aniline byproduct. Herein we report that a metal cluster containing 36 gold atoms capped by 24 thiolate ligands provides a unique pathway for nitrobenzene hydrogenation to achieve a -aminophenol selectivity of ∼100%. The gold cluster can efficiently suppress the over-hydrogenation of amino groups hydroxyl rearrangement with the aid of water and sequentially the proton transfer promoted by acid toward -aminophenol.

Diachronic evolvement from tetra-icosahedral to quasi-hexagonal close-packed bimetal clusters.

Here we report a diachronic evolvement from tetra-icosahedral AuAg(C[triple bond, length as m-dash]CR) to quasi-hcp (hexagonal close-packed) AuAg(C[triple bond, length as m-dash]CR) a one-step reduction, in which the size/structure conversion of the two clusters is not a typical Oswald growth process, but involves interface shrinking followed by core rearrangement and surface polymerization. AuAg(C[triple bond, length as m-dash]CR) has an aesthetic AuAg kernel that is composed of four interpenetrating AuAg icosahedra, while AuAg(C[triple bond, length as m-dash]CR) has a twisted Au core capped by a AuAg shell that are stacked in a layer-by-layer manner with a quasi-hcp pattern. The discovery of the two clusters not only provides further evidence for icosahedral clusters with longer excited-state lifetime compared to hcp-like clusters, but also discloses a double increase in catalytic reactivity for electrocatalytic oxidation of ethanol over quasi-hcp clusters in comparison with icosahedral clusters.

Evolution from superatomic AuAg monomers into molecular-like AuAg dimeric nanoclusters.

Hierarchical assembly of nanoparticles has been attracting wide interest, as advanced functionalities can be achieved. However, the ability to manipulate structural evolution of artificial nanoparticles into assemblies with atomic precision has been largely unsuccessful. Here we report the evolution from monomeric AuAu into dimeric AuAg nanoclusters: AuAg inherits the kernel frameworks from parent AuAg but exhibits distinct surface motifs; AuAg is racemic, while AuAg is mesomeric.

Cd-driven surface reconstruction and photodynamics in gold nanoclusters.

With atomically precise gold nanoclusters acting as a starting unit, substituting one or more gold atoms of the nanocluster with other metals has become an effective strategy to create metal synergy for improving catalytic performances and other properties. However, so far detailed insight into how to design the gold-based nanoclusters to optimize the synergy is still lacking, as atomic-level exchange between the surface-gold (or core-gold) and the incoming heteroatoms is quite challenging without changing other parts. Here we report a Cd-driven reconstruction of Au(DMBT) (DMBT = 3,5-dimethylbenzenethiol), in which four Au(DMBT) staples are precisely replaced by two AuCd(DMBT) staples to form AuCd(DMBT) with the face-centered cubic inner core retained.

The precise editing of surface sites on a molecular-like gold catalyst for modulating regioselectivity.

It is extremely difficult to precisely edit a surface site on a typical nanoparticle catalyst without changing other parts of the catalyst. This precludes a full understanding of which site primarily determines the catalytic properties. Here, we couple experimental data collection with theoretical analysis to correlate rich structural information relating to atomically precise gold clusters with the catalytic performance for the click reaction of phenylacetylene and benzyl azide.

Excitonic AuRu(PPh)(SCHPh) cluster for light-driven dinitrogen fixation.

The surface plasmon resonance of metal nanoparticles has been widely used to improve photochemical transformations by plasmon-induced charge transfer. However, it remains elusive for the molecular-like metal clusters with non-metallic or excitonic behavior to enable light harvesting including electron/hole pair production and separation. Here we report a paradigm for solar energy conversion on an atomically precise AuRu cluster supported on TiO with oxygen vacancies, in which the electron-hole pairs can be directly generated from the excited AuRu cluster and the TiO support, and the photogenerated electrons can transfer to the Ru atoms.